The article by Van Jacobson et al, entitled “Networking Named Content” and published in 2009 in the proceedings of the CoNEXT '09 conference presents a new content-centric architecture, called “Content-Centric Networking”. This architecture proposes changing the current communication model based on physical addressing in the network to a new communication model based on addressing by content name.
A stream can be supplied for different applications, real time or not, and is identified in the communication network by a stream name or identifier. A stream is made up of data segments. For its part, a data segment is identified by a segment number and the stream identifier.
More specifically, to obtain a data segment of a stream, a client entity transmits a request relating to this data segment, called “Interest Packet”. Upon reception of this request, a routing node checks to see if it has the data segment sought. If such is the case, it then transmits it to the interface via which the request was received, thus to the client entity, if appropriate via other routing nodes. If it does not have the data segment sought, it checks in a pending requests table PIT (Pending Interest Table), to see if it has already transmitted a request relating to the same data segment. If such is not the case, it stores, in the pending requests table PIT, the identifier of the data segment sought in association with an identifier of the interface via which the request relating to the data segment sought was received. It then routes the request in the communication network as a function of the stream identifier. Otherwise, that is to say when the pending requests table already contains the identifier of the data segment sought, it does not transmit the request received but associates, in the pending requests table PIT with the identifier of the data segment sought, an identifier of the interface via which the request was received. When the routing node receives the data segment sought, it retransmits it to all the interfaces via which requests relating to this data segment have been received, ultimately to all the client entities having requested it.
In the case of congestion provoked for example by an excessive volume of data segments to be routed, a routing node will not be able to immediately transmit one or more data segments. This or these segments will then be stored in queue, possibly even deleted when the latter is saturated. It is found that, in this type of communication network, the role of each routing node is to aggregate the requests relating to one and the same data segment of a stream. The absence of routing of a data segment has the effect, by virtue of the aggregation function of the routing nodes, of not satisfying a plurality of client entities having requested the latter. The number of client entities concerned depends on a degree of aggregation applied in the processing of the requests relating to a data segment of the stream. It should be recalled here that, in the conventional communication model, in a communication network with physical addressing, only one client entity is affected by the deletion of a packet or data segment that it has requested.